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ObjectivesTwo epidemiologic studies have found evidence of increasing risk of retinal detachment (RD) with increasing occupational lifting and related physical efforts. Beyond case reports, there is little evidence to explain this association. We hypothesise two alternative mechanisms and explore their implications for epidemiology.MethodsThrough literature review and discussions with retinologists, we developed hypotheses that predict different etiologic time windows for an effect of lifting on RD. The role of myopia in RD is better-understood, and provides important clues about possible roles of physical activity. Inter-ocular pressure (IOP) is likely to play a mediating role, and there are experimental studies of the effects of physical activity on IOP that may also provide useful evidence for understanding RD.Results and ConclusionsHypothesis 1: brief increases in IOP caused by lifting increase the risk of retinal tears during posterior vitreous detachment (PVD) - a normal ageing process. This suggests that there may be an elevated risk of retinal tear in the weeks following PVD. If this is correct, lifting during other times may not increase risk. Hypothesis 2: A long, slow pattern of increases in IOP from regular heavy lifting accelerates vitreous liquefaction, so that retinal tears are more likely to occur. Under this hypothesis, changes in IOP don’t cause tears directly, but instead a long-term pattern of ”peaks” in IOP may increase the chances of an RD. If this is correct, risk of RD would be associated with a longer history of heavy lifting.

ObjectivesAs the evidence on the possible association between lifting and retinal detachment (RD) is limited and controversial, we analysed a large population-based cohort to investigate the risk of RD arising from occupational lifting.MethodsWe assessed the incidence of surgically treated RD occurring between 1991 and 2009 in a national cohort of 49,321 Swedish men conscripted for military service in 1969–1970. We applied a job exposure matrix to occupational data from the 1990 census to estimate the frequency of heavy lifting (>20–25 kg) at the workplace. We fitted Poisson regression models including lifting, myopia, income, and education level to estimate incidence rate ratios (IRR) and 95% confidence intervals of RRD.ResultsWe analysed 217 RD cases that occurred in 7 80 166 person-years. Estimates adjusted by myopia and socioeconomic factors support the hypothesis that the risk of RD increases among subjects lifting heavy weights at least twice per week, compared to workers not performing lifting (IRR 2.38, 95% CI 1.15–4.93, p for trend across lifting categories 0.014). Myopia was a strong negative confounder of the lifting - RD association. While RD was rare in the entire cohort (0.28 cases per 1000 person-years), the rate peaked at 7.9 per 1000 person-years among workers frequently lifting heavy loads, aged between 50 and 59 years, and affected by severe myopia.ConclusionsOur study provides evidence that performing heavy occupational lifting increases the risk of RD, while myopia and socioeconomic factors may be important negative confounders of this association.

IntroductionThis study investigated the hypothesis that common occupational and environmental chemical exposures with known irritant or sensitising properties trigger exacerbations for patients with chronic obstructive pulmonary disease (COPD). MethodsWe conducted a case crossover study in 168 COPD patients who were members of a disease management group (DMG) in central Massachusetts. Participants completed a baseline health survey and several short exposure surveys. Exposure surveys were administered by a nurse when a participant telephoned to report an exacerbation (case periods) and at a maximum of 3 randomly identified control periods when they were not experiencing an exacerbation. We compared exposures in the week preceding an exacerbation with exposures in normal (non-exacerbation) weeks. The questionnaire assessed short-term (one week) home, community and workplace activities and exposures that may be associated with COPD exacerbation.ResultSelf-reported exercise was protective (OR=0.59 95% CI: 0.35–1.00). Among the chemical exposures, car and truck exhaust (OR=4.36, 95% CI: 1.76–10.80) and use of scented laundry products (OR=2.69, 95% CI: 1.31–5.52) showed strong positive effects. Self-reported respiratory infections were strongly associated with COPD exacerbation (OR=7.90, 95% CI: 4.29–14.50). Variations in outdoor temperature were associated with COPD exacerbation risk (moderate versus cold temperature OR=1.95, 95% CI: 0.26–0.70).DiscussionThese results suggest that some environmental chemical exposures may play a role in triggering COPD exacerbations. If confirmed, they may provide useful guidance for COPD patients to better manage their diseases.

ObjectivesWhile there is evidence of asthma and other respiratory illness among workers performing cleaning and disinfecting (C and D) of environmental surfaces in healthcare and in residential and institutional settings, quantitative measurements of C and D exposures are limited. Previously, we found that 80% of home care (HC) aide visits to clients’ homes involve C and D; commonly-used C and D products contain bleach, a respiratory irritant. Objectives of this study were to measure quantitatively airborne exposures generated during C and D tasks performed by HC aides using a bleach-containing product. The work reported here is part of a larger evaluation of exposures and respiratory effects of a range of C and D products and practices and their efficacy in reducing pathogens in HC.MethodsA bathroom was constructed in a laboratory according to home building construction specifications. Twenty HC aides were recruited from employer agencies to perform C and D tasks for 20 min sessions in the bathroom following typical HC practices using a C and D spray product containing bleach (1%–5% by weight sodium hypochlorite). Aides wore a vest holding a direct-reading instrument to measure chlorine breathing-zone concentrations as they performed C and D on tub/shower, toilet, and sink.ResultsMaximum chlorine concentrations generated during the 20 min sessions ranged from 0.35ppm to 3.40ppm. The tub/shower C and D task produced the highest exposures. The US Occupational Safety and Health Administration ceiling limit for chlorine is 1 ppm; nearly 70% of the aides conducted a C and D session exceeding this value.ConclusionsC and D in HC using a product containing bleach can produce over-exposure to chlorine, a respiratory irritant.

ObjectivesTo support a case-control study investigating the association between occupational lifting and retinal detachment (RD) in Massachusetts, we estimated and compared self-reported lifting exposures to those documented in O*NET, a government database that characterises physical exposures such as manual material handling and vibration for hundreds of U.S. job titles.MethodsCases of RD were identified based on recent surgical treatment and controls based on a recent routine eye exam. All recruited participants were mailed a questionnaire including questions on the magnitude and frequency of lifting, pushing and pulling in all previous jobs. To help patients recall physical exertion across their lives, photos of lifting common objects were included. Participant responses were used to estimate occupational lifting exposures in three ways: 1) self-reports; 2) a job exposure matrix (JEM) linking job titles with O*NET exposure data; and 3) combining 1 and 2 with Empirical Bayes Estimators (EBE).ResultsStudy recruitment will continue through 2017, enrolling at least 150 cases and 250 controls. Preliminary analyses from half of the participants indicate an average of four jobs/person. Self-reports and job-title based exposures from O*NET were moderately correlated for lifting (Spearman rank correlation=0.48, p<0.0001). Frequent reports of whole body vibration exposures were uncommon (<5% of all jobs), suggesting the study will have less power to evaluate this exposure.ConclusionsBy combining strengths of JEMs with personal recall, this study sought to improve on previous investigations. EBE provide a formal method for optimising the two types of data.